he is right bro, we don't need different gears but different ratio's to keep the engine in optimal torque or economy range according to load. cvt doesn't have infinite ratios(from a mechanical engineer's point of view as it would be an IVT than and would be very costly to build) but its single gear(driven by belts and pulleys that change ratio according to hydraulic pressure applied by tcu) can have varying ratios. to explain cvt in layman's terms think of two gears, one has a fixed size while other is shaped like a cone. the fixed size one can move across the cone which varies in size(ratios) smoothly while in normal tranny 4 or 5 gears are cut into fixed sizes. cvt to conventional tranny's what ramps are to stairs. and about different gear ratios that we feel, manufacturer programs them in tcu because the drivers of cvt complain that it is too numb(smooth) and also while accelerating the engine may rev at a single speed(like at 2k constantly from 40kph to 80kph), it sounds annoying like a boat accelerating(also called droning).